Subject: Re: bootstrap?
To: None <mw@eunet.ch>
From: Hamish Macdonald <hamish@border.ocunix.on.ca>
List: amiga
Date: 01/10/1995 18:35:00
>>>>> On Tue, 10 Jan 1995 13:09:39 -0500,
>>>>> In message <199501101809.TAA24677@eunet.ch>,
>>>>> mw@eunet.ch wrote:

mw> Eh, sorry... the Amiga is not a PC, we don't need a second
mw> "bootmanager", we already have one!

mw> If you want a partition to autoboot, you set the flag, and you set
mw> the priority according to your needs. If you want to override the
mw> default partition, you go into the bootmenu and select the
mw> partition you want to boot from.

Yup, you can do this with amiga lilo.

mw> There's no good reason to reinvent the wheel here, even if it may
mw> sound tempting to reuse existing lilo-code..

Amiga lilo doesn't allow you to select a partition.

>> - AmigaOS loads the boot block

>> - the boot block loads a loader (AmigaOS executable residing on a
>> Linux/68k partition)

mw> Should probably be more generic, not OS-related.

Well, it has to be an AmigaOS executable, in a sense, since it will be
using AmigaOS Exec routines and devices.

The bootblock relocates the AmigaOS executable before running it.

The bootblock nicely provides some routines for
reading files to the secondary loader.

The loader itself does have to be somewhat OS-related (in terms of
what it does), since configuration information has to be passed to the
kernel, and this sort of this is OS-specific.

In the case of NetBSD, this becomes a simple manner of adapting
loadbsd to use the mechanisms Geert has provided, and either priming
loadbsd with the block offsets of the kernel, or teaching the
loader/loadbsd to read a bffs partition.

mw> NOT. The loader boots the kernel from the partition the user has
mw> chosen to boot from. For special cases, where you want to boot
mw> using certain flags, or different images, you use loadbsd like you
mw> did before. Autoboot a normal configuration, boot using some
mw> monitor-program (whether that resides in a PROM or runs under a
mw> different OS is a minor difference) if you want to override the
mw> default.

I agree with you, that the choice should be left out from the loader.
The loader should just load the executable it has been configured
with.

mw> So, no I don't think your approach sounds appropriate for the
mw> amiga, sorry :-)

You should look at the code first :-)

It works better than what currently exists, and it is easy to throw
away the querying.